This invention relates to an apparatus for controlling movement of a throttle valve in response to a change in the position of an accelerator pedal.
In order to meter the amount of air to an internal combustion engine, a variable positionable throttle valve is situated within the induction passage of the engine. Normally, a mechanical link mechanism is provided to couple the throttle valve to an accelerator pedal in a manner to move the throttle valve in response to movement of the accelerator pedal. In order to improve the responsiveness of the movement of the throttle valve with respect to the movement of the accelerator pedal, it has been proposed to substitute an electrical servo control system for the mechanical link mechanism. Such an electrical servo control system includes a potentiometer which converts the movement of the accelerator pedal into a corresponding electric signal which is electrically processed to drive an actuator which thereby moves the throttle valve to a position corresponding to the new position of the accelerator pedal. If the control system is subject to failure resulting in improper throttle valve control, however, the vehicle occupant will be exposed to serious danger. This is true particularly when the throttle valve is retained at its open position.
In order to eliminate the problem attendant on the use of an electrical servo control system, it may be considered to provide a return spring effective to return the throttle valve to its closed position when the actuator is placed out of operation in the even of failure of the control system. However, this raises another problem in that the operator cannot drive the automotive vehicle to a place for repair.
Therefore, the present invention provides an improved throttle valve control apparatus which permits an operator to drive the automotive vehicle to a place for repair with the throttle valve being held at its closed position.